The present invention relates to industrial burners, especially to an industrial burner having high and low pressure blowers interconnected for directing high and low pressure air through different passageways into an industrial dryer.
Large high capacity fuel burners are generally used in industries requiring drying of various materials. For example, such burners are required for operating large rotary aggregate dryers and for kiln drying and processing of lime, bauxite, sand, coal, cement and the like. In the making of asphalt roads, drying units are used for drying the aggregate before mixing with the asphalt.
In drying aggregate, a typical unit may have a rotating horizontal drum in which wet rock is introduced into one end of the drum, carried to the top of the drum, and dropped back. The material is gradually carried to the opposite end of the drum and removed by a conveyor. A fuel burner is typically connected to a combustion chamber placed at one end of the drum. The hot gases and air emanating from the burner are directed through the falling aggregate, known as the aggregate curtain, and serves to dry out all moisture from the material. An exhaust fan at the output end of the drum draws the heat of the air therethrough. The gas temperature at the burning input end may be on the order of 2400 degrees Farenheit, dropping to about 350 at the opposite end of the drum. In large dryers, such as this, the burners are required to produce large amounts of heat on a continuous basis.
In the past, a variety of burner fuels have been utilized but recently burners have tended to use natural gas or fuel oil. The present invention can utilize natural gas, LP, pulverized coal or fuel oil as desired and depending upon the burner head utilized. The absence of certain types of fuels in different parts of the country has resulted in entire manufacturing plants not being able to operate because of the lack of the type of fuel the plant is set up to use. As a result of this, many industrial burners are being designed to use more than one type of fuel and may for instance switch from oil to natural gas as price and availability dictate.
The present invention is for a high efficiency burner using a high pressure turbo blower and a high efficiency, low noise, air flow centrifugal blower for low pressure air and utilizes one air intake into the burner through one set of control dampers for total air control in a simplified burner design. The high pressure and low pressure blowers are interconnected to be driven by a single motor and positioned in a single housing for utilizing air from a single intake into the housing.